This paper discusses C.G. Hempel's contention according to which universal laws fulfil the same 'theoretical function' in natural and historical science. To this end, the author differentiates between system ·building and genetically structured sciences. Their modes of presentation are respectively hierarchically ordered theory and narrative. These two basic ways of arranging our knowledge are led back to a difference in explanation, of a pragmatic, not logical nature, that is, to the difference between subsumtion and ascription. Whereas in the systematic organization of knowledge, the basic underlying theory sets the exact conditions, under which a fact can be described as explained, such an epistemological directive function of laws is not to be found in genetic organization.